nrf5340dk: first flash issue

[emmanuelsearch]

Upon first flash of a brand new board, you get this error, related to #127 :

Running probe-rs run --chip nrf5340_xxAA ../../build/bin/nrf5340dk/hello-world/cargo/thumbv8m.main-none-eabi/release/hello-world

 WARN probe_rs::config::sequences::nrf: Core 0 is locked. Erase procedure will be started to unlock it.
Error: Connecting to the chip was unsuccessful.

Caused by:
    0: An ARM specific error occurred.
    1: An operation could not be performed because it lacked the permission to do so: erase_all

---

Running with the target flash-erase-all as specified in #128 fixes it but you still get a bunch of warnings (see below). What's to do about this?

warning: use of inline assembly is unsafe and requires unsafe block (error E0133)
  --> src/riot-rs-threads/src/arch/cortex_m.rs:82:5
   |
82 | /     asm!(
83 | |         "
84 | |             movw LR, #0xFFFd
85 | |             movt LR, #0xFFFF
...  |
88 | |         options(noreturn)
89 | |     );
   | |_____^ use of inline assembly
   |
   = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
   = note: inline assembly is entirely unchecked and can cause undefined behavior
note: an unsafe function restricts its caller, but its body is safe by default
  --> src/riot-rs-threads/src/arch/cortex_m.rs:81:1
   |
81 | unsafe extern "C" fn SVCall() {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: requested on the command line with `-W unsafe-op-in-unsafe-fn`

warning: use of inline assembly is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/arch/cortex_m.rs:122:5
    |
122 | /     asm!(
123 | |         "
124 | |             mrs r0, psp
125 | |             cpsid i
...   |
145 | |         options(noreturn)
146 | |     );
    | |_____^ use of inline assembly
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: inline assembly is entirely unchecked and can cause undefined behavior
note: an unsafe function restricts its caller, but its body is safe by default
   --> src/riot-rs-threads/src/arch/cortex_m.rs:121:1
    |
121 | unsafe extern "C" fn PendSV() {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: call to unsafe function `critical_section::CriticalSection::<'cs>::new` is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/arch/cortex_m.rs:220:14
    |
220 |     let cs = CriticalSection::new();
    |              ^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: consult the function's documentation for information on how to avoid undefined behavior
note: an unsafe function restricts its caller, but its body is safe by default
   --> src/riot-rs-threads/src/arch/cortex_m.rs:219:1
    |
219 | unsafe fn sched(old_sp: usize) -> usize {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: dereference of raw pointer is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/arch/cortex_m.rs:225:34
    |
225 |             if let Some(pid) = (&*THREADS.as_ptr(cs)).runqueue.get_next() {
    |                                  ^^^^^^^^^^^^^^^^^^^ dereference of raw pointer
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior

warning: call to unsafe function `cortex_m::interrupt::enable` is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/arch/cortex_m.rs:232:9
    |
232 |         cortex_m::interrupt::enable();
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: consult the function's documentation for information on how to avoid undefined behavior

warning: dereference of raw pointer is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/arch/cortex_m.rs:238:24
    |
238 |     let threads = &mut *THREADS.as_ptr(cs);
    |                        ^^^^^^^^^^^^^^^^^^^ dereference of raw pointer
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior

warning: use of inline assembly is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/arch/cortex_m.rs:265:5
    |
265 |     asm!("", in("r1") current_high_regs, in("r2") next_high_regs);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ use of inline assembly
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: inline assembly is entirely unchecked and can cause undefined behavior

warning: call to unsafe function `critical_section::CriticalSection::<'cs>::new` is unsafe and requires unsafe block (error E0133)
   --> src/riot-rs-threads/src/lib.rs:178:14
    |
178 |     let cs = CriticalSection::new();
    |              ^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function
    |
    = note: for more information, see issue #71668 <https://github.com/rust-lang/rust/issues/71668>
    = note: consult the function's documentation for information on how to avoid undefined behavior
note: an unsafe function restricts its caller, but its body is safe by default
   --> src/riot-rs-threads/src/lib.rs:176:1
    |
176 | pub unsafe fn start_threading() {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: `riot-rs-threads` (lib) generated 8 warnings (run `cargo fix --lib -p riot-rs-threads` to apply 4 suggestions)
    Finished `release` profile [optimized + debuginfo] target(s) in 0.50s
     Running `probe-rs run --chip nrf5340_xxAA ../../build/bin/nrf5340dk/hello-world/cargo/thumbv8m.main-none-eabi/release/hello-world`
 WARN probe_rs::architecture::arm::core::armv8m: The core is in locked up status as a result of an unrecoverable exception
 WARN probe_rs::architecture::arm::core::armv8m: The core is in locked up status as a result of an unrecoverable exception
      Erasing ✔ [00:00:00] [############################################################################################################################################] 8.00 KiB/8.00 KiB @ 29.56 KiB/s (eta 0s )
  Programming ✔ [00:00:00] [############################################################################################################################################] 8.00 KiB/8.00 KiB @ 24.12 KiB/s (eta 0s )    Finished in 0.681s
riot_rs_rt::startup()
nrf5340dk::init()
nrf5340::init()
riot-rs-embassy::init()
riot-rs-embassy::init_task()
riot-rs-embassy::init_task() done
Hello from main()! Running on a nrf5340dk board.
 WARN probe_rs::session: Could not clear all hardware breakpoints: An ARM specific error occurred.

Caused by:
    Timeout occurred during operation.

[kaspar030]

So the Rust warnings are our zealous linter settings. Yeah we need to something about them.

WARN probe_rs::session: Could not clear all hardware breakpoints: An ARM specific error occurred.

Caused by: Timeout occurred during operation.

This I've seen, too. I don't know what it is. I didn't give it much thought b/c apart from the warning, everything works fine.